Conveyor belts for the conveyance of articles may comprise balls or rollers which can rotate. The articles can be quickly sorted during conveyance on such conveyor belts as they can be unloaded while being slid to a side of the conveyance line (see Japanese Laid-Open Patent Publication No. 2003-182829).
In such a conveyor belt, the belt module comprises vertically laminated first and second members. The conveyor belt is formed by connecting hinge portions formed in the first and second members of the modules by the use of hinge pins. Between the first and second members are balls or rollers which can rotate and allow for the articles to be discharged by sliding to a side of the conveying line.
However, the above-mentioned conventional conveyor belts comprise belt modules formed by vertically integrated first and second members wherein the balls are sandwiched between the first and second members. This formation causes sliding wear between the belt module and the balls.
Further, such conveyor belts comprise a belt module and balls that are made of polyacetal, which has excellent self-lubricating property so as to suppress sliding wear. Because the materials of the belt module and the ball are the same, however, the contact surfaces between the belt module and ball have high affinity and are likely to adhere to each other, thereby resulting in increased sliding wear.
Therefore, the above described belts have problems with accelerated wear. Further, a backlash in the conveyor belt or a change in the conveying level can occur due to the extra wear, whereby articles loaded on the balls of the belt cannot be conveyed stably. Additionally, the sliding wear will lead to the contamination of the conveyance environment with the powder and dust generated by the sliding wear.